In recent years, there are known multi-chamber apparatuses in which various substrate treatments can be consistently carried out under vacuum by arranging a plurality of process chambers around a transfer chamber so as to center on the transfer chamber and connecting them via gate valves, as substrate processing apparatuses for processing substrates to be processed, such as semiconductor wafers and glass substrates for liquid crystal display devices under vacuum. The multi-chamber type vacuum processing apparatus of this type is provided with a substrate transfer apparatus for automatically carrying in/out the substrates from the transfer chamber to each of the process chambers.
As the substrate transfer apparatus, a parallel link type apparatus as shown in FIG. 7 is known (see Patent Document 1 below), for example. The parallel link type substrate transfer apparatus 5 shown in the figure includes a pair of rotating shafts 1, 2 to at least one of which a driving source is connected, first arms 11, 12, one end of each of which is connected to the rotating shafts 1, 2, a pair of second arms 21, 22, one end of each of which is rotatably connected to the corresponding one of the other ends of the first arms 11, 12, and a hand 4 rotatably coupled to each of the other ends of the second arms 21, 22.
The first arms 11, 12 and the second arms 21, 22 have the same arm length and form a parallel link mechanism. Therefore, by rotating the rotating shafts 1, 2 in opposite directions, angles 8 respectively formed by the first arms 11, 12 and the second arms 21, 22 change, and the hand 4 is moved in upward and downward directions in the figure. Accordingly, it becomes possible to transfer a substrate W on the hand 4 to any position.    Patent Document 1: Japanese Patent Application Laid-open No. Hei 9-283588    Patent Document 2: Japanese Patent Application Laid-open No. 2004-228370